In tests on 145 Baltimore-area men and women with existing atherosclerosis, all over age 65, researchers found that after 18 months of drug therapy, reductions in arterial wall thickness were measurably no different between the half who took dual niacin-statin therapy and the rest who remained on statin therapy alone. "

The results of well-conducted trials of vitamin D lead to the conclusion that the current U.S. National Academy of Sciences-Institute of Medicine upper limit for vitamin D intake of 2000IU per day 1, 37 is excessively conservative. That intake would raise serum 25(OH)D by an average of about 50 nmol/L (20 ng/mL), well within the safe range of serum 25(OH)D concentrations that extends to 500 nmol/L (200 ng/mL). Intake of 4,000IU per day would raise serum 25(OH)D by an average of about 100 nmol/L (40 ng/mL). Even prolonged physiologic-replacement intake of 10,000IU per day of vitamin D3 would pose no known risk of adverse effects in virtually all adults.